Effenbergerite
| Effenbergerite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1993-036 |
| chemical formula | BaCu [Si 4 O 10 ] |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.EA.05 ( 8th edition : VIII / H.02) 71.02.03.03 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | ditetragonal-dipyramidal; 4 / m 2 / m 2 / m |
| Space group | P 4 / ncc (No. 130) |
| Lattice parameters | a = 7.44 Å ; c = 16.13 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {001}, occasionally also {100}, {1l0} and {102} |
| Physical Properties | |
| Mohs hardness | 4 to 5 |
| Density (g / cm 3 ) | measured: 3.57 (2); calculated: 3.52 |
| Cleavage | completely after {001} |
| Break ; Tenacity | slightly mussel-like |
| colour | blue to blue-violet |
| Line color | Light Blue |
| transparency | transparent to translucent |
| shine | Greasy gloss, glass gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.633 n ε = 1.593 |
| Birefringence | δ = 0.040 |
| Optical character | uniaxial negative |
| Pleochroism | Strong: ω = dark blue; ε = light blue to almost colorless |
Effenbergerite is a very rarely occurring mineral from the mineral class of " silicates and germanates ". It crystallizes in the tetragonal crystal system with the composition Ba [Si 4 O 10 ] and is therefore chemically seen a barium - copper - layered silicate .
Effenbergerite is transparent and usually develops tabular crystals a few millimeters in size and blue to blue-violet in color with light blue streak color . Uninjured crystal surfaces usually have a fat-like gloss , cleavage surfaces and fracture surfaces, on the other hand, have a somewhat weaker glass gloss.
Etymology and history
Effenbergerite was first discovered during an excursion to South Africa in the "Wessel's Mine" (Wessels Mine) near Hotazel in the manganese field of the South African Kalahari . The mineral was described in 1994 by Giester and Rieck, who named it after the mineralogist and geologist Herta Silvia Effenberger (* 1954) from the University of Vienna , in recognition of their work in the field of stereochemistry of bivalent copper, which led to numerous crystal structure determinations; including many minerals and some new mineral types.
classification
In the meantime outdated, but still in use 8th edition of the mineral classification by Strunz of Effenbergerit belonged to the mineral class of "silicates and Germanates" and then to the Department of "phyllosilicates (phyllosilicates)" where he collaborated with Bigcreekit , Cuprorivait , gillespite , sanbornite and Wesselsit formed the unnamed group VIII / H.02 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns effenbergerite to the class of “silicates and germanates” and there to the “phyllosilicates” section. However, this section is further subdivided according to the structure of the layers, so that the mineral can be found according to its structure in the sub-section "Simple tetrahedral networks with 4, 5, (6) and 8 participating rings", where it can be found together with Cuprorivait, Gillespit, Wesselsit forms the unnamed group 9.EA.05 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns effenbergerite to the class of "silicates and Germanates" and there in the section of "layered silicate minerals". Here he is together with Cuprorivait, Gillespit and Wesselsit in the " Cuprorivait group " with the system no. 71.02.03 within the sub-section of "Layered Silicates: Layers of six-membered rings with 2: 1 layers".
Crystal structure
Effenbergerite crystallizes tetragonally in the space group P 4 / ncc (space group no. 130) with the lattice parameters a = 7.44 Å and c = 16.13 Å as well as 4 formula units per unit cell .
Education and Locations
Effenbergertite was found within pectolite veins, embedded in a matrix of Braunite , Sugilite and Hausmannite . Other accompanying minerals were copper , calcite , quartz and clinozoisite .
So far (status: 2018) Effenbergerite could only be detected at its type locality "Wessel's Mine" in South Africa.
use
Effenbergerite was already synthetically produced in ancient China and is still known and used today as the pigment "Han blue".
See also
literature
- G. Giester, B. Rieck: Effenbergerite, BaCu [Si 4 O 10 ], a new mineral from the Kalahari Manganese Field, South Africa: description and crystal structure . In: Mineralogical Magazine . tape 58 , December 1994, p. 663–670 ( arizona.edu [PDF; 576 kB ; accessed on April 8, 2018]).
Web links
- Mineral Atlas: Effenbergerite (Wiki)
- Effenbergerite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed December 27, 2018 .
- American-Mineralogist-Crystal-Structure-Database - Effenbergerite. In: rruff.geo.arizona.edu. Retrieved December 27, 2018 .
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 658 .
- ^ David Barthelmy: Effenbergerite Mineral Data. In: webmineral.com. Retrieved December 27, 2018 .
- ^ A b c d G. Giester, B. Rieck: Effenbergerite, BaCu [Si 4 O 10 ], a new mineral from the Kalahari Manganese Field, South Africa: description and crystal structure . In: Mineralogical Magazine . tape 58 , December 1994, p. 663–670 ( arizona.edu [PDF; 576 kB ; accessed on April 8, 2018]).
- ↑ a b c d Effenbergerite. In: mindat.org. Hudson Institute of Mineralogy, accessed December 27, 2018 .
- ↑ Find location list for Effenbergerite at the Mineralienatlas and at Mindat
- ↑ 10072 Han blue, barium copper frit. (PDF 792 kB) In: kremer-pigmente.com. Kremer Pigments, January 18, 2018, accessed December 27, 2018 .